Preliminary Study on Release Rule of Cr~(6+) from River Sediments
WANG Yu-juan et al(College of Environmental Science and Engineering,Guangdong University of Technology,Guangzhou,Guangdong 510006)
[Objective] The aim was to study the release rule of the Cr6+ from the river sediments.[Method] With the sediment from Beijiang River as the studying object,the effects of the change of each factor from water on the releasing amount of Cr6+ from the river sediment samples were studied through simulating the change of the environmental conditions.[Result] The amount of precipitates of Cr6+ from the sediment samples increased gradually with the increasing of the temperature and that decreased gradually with the increment of the pH value.When the pH value was above 8,the amount of precipitates of Cr6+ increased in a smaller range.The amount of precipitates of Cr6+ increased in a larger range with the increment of the concn.of NaCl solution and when the concn.of NaCl was above 2 g/L,the amount of precipitates of Cr6+ showed slide phenomenon.The releasing amount of Cr6+ increased gradually with the increment of the concn.of positive ion in the acid rain and reached a peak value and then decreased gradually with the increment of the concn.of negative ion.[Conclusion]The research provided the basis for discussing the problem of the secondary pollution of Cr6+ from the river sediments.